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Hello, hello, everyone, and welcome to another edition of the �������� Blog. Today, I’ve finally found some time to actually write, and I’m doing it at one of my favorite places of all time: . For those who are unfamiliar, Claire’s is a vegan-vegetarian eatery in New Haven that has kind staffing and a Lithuanian coffee cake to die for.

Speaking of food, in past blogs, I’ve gone into depth on the microbiome, what the heck this thing is, and the foods that best nourish the microbiota (henceforth nourishing you). However, something that’s really piqued my interest is how one’s microbial gut population influences their neurological health.

Here in the U.S., Alzheimer’s accounts for 60-80 percent of all dementias (Zhu et al.), which is defined as impaired ability for the brain to function. Dementia is something that will happen to all of us as we age – as well as the decline of our body cells as a whole – but the degree and rate of which this happens can be determined by how one lives their life. For example, when people ask me what muscle is the most important to train, I reply with my own question:

“What do you want to be stronger: your heart or your bicep?”

While the brain isn’t physiologically a muscle, it certainly works like one. The more you use it, the better it functions. It’s one of the reasons why they start memorization so early on in your academic life: to build the neural pathways that strengthen one’s ability to remember and actively recall things. The brain is incredibly adaptive, and, because of that, a lot of interesting things tend to happen. Your ability to form biases quickens, the time it takes for you to solve problems similar to one another shortens, and so on and so forth. Your brain can be your best or worst friend, basically. Choose which one you want.

So, Alzheimer’s. The pathophysiology of this disease is characterized by the deposition of amyloid beta, leading to the formation of hyperphosphorylated tau protein (which composes plaques and neurofibrillary tangles) that results in synapse loss and neuronal death (Zhu et al.). Synapses allow brain cells (neurons) to communicate with one another, similar to how a cell phone signal works. Without synapses, the brain can’t talk to itself and nothing happens, adding up to the scary neurological degeneration Alzheimer’s patients experience. However, remember that the rate of this deterioration (note that we’re not all susceptible to this disease. I would go through your family’s history with a fine-toothed comb) is a variable dependent on lifestyle.

Use brain = brain stays.

Not use brain = brain doesn’t pay rent.

As the medical field continues to find new treatments and potential cures to neurodegenerative diseases, the recognition of the fact that the “gut microbiome plays important roles in human physiology and pathophysiology” (Zhu et al.) is very promising for those in the field of nutrition & dietetics. In fact, a large number of studies have been linked to intestinal microbiome diseases to those such as inflammatory bowel disease, irritable bowel syndrome, colon cancer, neurological diseases (i.e. Alzheimer’s and Parkinson’s), metabolic diseases, musculoskeletal diseases, osteoporosis, and gout (Zhu et al.).

Similar to how neurons “talk” to one another via synapses, the brain and gut are very interlinked, using the vagus nerve (X) as a communication highway between them. Similarly, when one is out of balance, the other can be equally as affected. Personally, if I’m too stressed out, I will not eat a single thing. Likewise, if my stomach hurts, I can be a pretty irritable person.

Speaking of behavioral patterns, “Key metabolites of gut microbes include short chain fatty acid (SCFAs), such as acetate and butyrate, which can play important roles in regulating the brain and behavior through G protein coupled receptors” (Zhu et al.). Please keep in mind that SCFAs are formed by the indigestion of fiber, and that the function of SCFAs is primarily to support the intestinal wall of the GI tract as to protect the body from any funky visitors that may slip through the mucosal barrier. What’s more important? Intestinal microbes are capable of secreting neurotransmitters such as norepinephrine (Alpha-1 adrenergic receptors), dopamine, and gamma-aminobutyric acid (Zhu et al.). NTs (neurotransmitters) are chemical messengers of the brain, similar to how hormones are the chemical messengers of the body.

Alright, let’s back up a little bit and look at this big picture for a second.

Proper nutrition → good microbiome → good brain-body communication → happy human being → continuation of proper nutrition → repeat.

When looking at those with Alzheimer’s, a clinical trial “demonstrated a lower abundance of Eubacterium rectale and Bacillus subtilis and a higher abundance of Escherichia/Shigella in their stools compared to other groups” (Zhu et al.). The latter two species of bacteria are fairly nasty ones; these are the ones commonly associated with food-borne illnesses causing a plethora of symptoms in the host.

More concerningly, the “microbiome of the elderly with AD shows a lower proportion of bacteria synthesizing butyrate that contributes anti-inflammatory activity and immunity regulation, as well as greater abundance of taxa that are known to cause pro-inflammatory states” (Zhu et al.). Summarily, what we’re seeing is that with age, one’s gut microbiota composition becomes increasingly dysfunctional – along with the rest of the body.

So...what’s the solution?

Well, we start with pro, pre and synbiotics. These bad boys – as mentioned in earlier articles – are what constitute, nourish, and help support pre-existing microbiome colonies in the GI tract. Interestingly enough, in a study done by Akbari et al., they “found that, compared to AD patients treated with normal milk, patients who consumed milk rich in multiple Lactobacillus and Bifidobacterium species showed a significant (P less than 0.001) improvement in the mini-mental state examination (MMSE) score” (Zhu et al.).

To spare you the Google: (P less than 0.001) equates to a one in a one thousand chance. Probably.

Both Lactobacillus and Bifidobacterium are vital species of the gut microbiome. While I’d love to talk about them more, I’m almost at four Google Doc pages and I’m not sure if my editors will like that, lol.

In summary, there is a trend across the health science field that when the gut microbiome is established, maintained, and given the nutrients it needs to prosper, it does a rather good job of offering the host a variety of health benefits. Taking Alzheimer’s in particular, I believe there is hope to have in buffering the effects of the disease with further research into the gut-brain connection through the work of clinical trials. Who knows? Maybe the microbes have been the answer all along. I’m not saying neurodegenerative disorders will be cured or a cure will be established, but I’m a firm believer that a more holistic, non-invasive treatment may be plausible in the future.

I hope everyone is having a fantastic week, and that finals aren’t getting anyone down. You can only do your best, and that’s all anyone can ask for.

You got this.

With peace, love, and peanut butter,
Beatrice

Beatrice Glaviano ’26 is a nutrition sciences major at the University of New Haven.

Works Cited

Ruairi Robertson, PhD. “Why Bifidobacteria Are so Good for You.” Healthline, Healthline Media, 25 July 2017, www.healthline.com/nutrition/why-bifidobacteria-are-good. Accessed 30 Apr. 2024.

Zhu, Xueling, et al. “The Relationship between the Gut Microbiome and Neurodegenerative Diseases.” Neuroscience Bulletin, vol. 37, 3 July 2021, link.springer.com/article/10.1007/s12264-021-00730-8, https://doi.org/10.1007/s12264-021-00730-8. Accessed 19 Apr. 2024.